Piaget based much of his theory of cognitive development on his observations of how his children interacted with the world as they grew. piaget's research method was and his scientific goal was

Naturalistic observation, Description.  

Explanation:

Naturalistic observation is a research method. It has been used in social psychology and another field to observe the behavior of animals and human beings in natural settings.

This research method is commonly used by the psychologist and the other scientist who want to study animal and human beings in natural settings. Many times what researchers want to study, does not happen in the laboratory.

The researcher has to do their study in natural settings, where what they want to study, occur naturally.  

Thus much of his study on cognitive development in children and how children respond to the environment, all happened in natural observation.

c.it was a major banking and commerce center.

d.leonardo da vinci

d. to fix corruption and problems in the catholic church

d. to reform the catholic church from within

a. human faces are presented in an idealized, spiritual manner.

good question. i'll be looking into that. (this is a joke sir)